Not receiving the mails with in the domain

We are a small business group using hotmail  email service from last 1 year. Till today 11 AM everything was fine, but from 11 Am on wards

we are facing a different problem with hotmail/outlook.com service.

1 we are able to send e mails to external email-ids ( eg: from hotmail acount to gmail account)

2 and we are able to receive the emails from external ids ( eg: gmail to hotmail)

3. But we are not able to send or may be receive hot mail to hotmail .

I have tested the problem as below.

sent a test mail to ten internal email ids with cc to external email ids. External people have revived the mail, but no internal people.

and the extrenal people replied the test mail, which recived by hotmail account.

but we are not able to fine why there a problem from hotmail to hotmail.

Our domain is @springforthcap.com

My mailid id *** Email address is removed for privacy ***

Please helps us.